Question from my state's fan site...

[Ref16]

Originally Posted by Adam

Yep, but the odds of them actually being able to remove some time are about 50/50, I'd say. At least one official would have needed to have a count of some kind; otherwise we'll be starting again with 21 seconds.

Well said.

Without definite knowledge of how much time should have passed then 21 seconds will remain on the clock. The coach handled it correctly, the score keeper needed to get the referees attention at that point.